snyder



G. R. SNYDER SUB-AQUATIC GUN Jan. 21, 1964 Filed Nov. 6. 1961 INVENTOR. GEORGE R. SNYDER ATTORNEY United States Patent 3,118,242 SUB-AQUATIQ GUN George ll. Snyder, Woodbri-dge, Conn, assignor to (lliu Mathieson Chemical Qorporation, New Haven, Conn, a corporation of Virginia Filed Nov. 6, 1961, Ser. No. %,581 3 Claims. (Cl. 4-2-1) This invention relates to an underwater spear gun and more particularly to a cartridge activated gun containing means of adjusting and controlling the velocity of the projectile.

In the operation of sub-aquatic spear guns, there are several reasons why it is desirable to control the velocity of the projectile carried therein. There is, of course, an important safety consideration which dictates that the spear should not be fired beyond the visibility of the gun operator. Also it is a desirable feature in such guns to be able to vary the projectile velocity commensurate with the size and nature of the desired target fish.

In the use of spear guns operated by spring or hydropneurnatic pressure, the desired projectile velocity can usually be attained by adjustments made during the cocking operation. However this is not possible during the operation of spear guns activated by blank cartridges developing nearly uniform amounts of gas pressure. A1- thou-gh such cartridge activated guns possess many advantages, control of the projectile velocity and range is one area wherein such guns have been deficient to date.

Therefore it is an object of this invention to provide a cartridge activated sub-aquatic gun containing means by which the projectile velocity and range may be adjusted and controlled.

It is a further object of this invention to provide a cartridge activated underwater spear gun having novel barrel features wherein improved safety characteristics during operation of the gun are obtained.

Still another object of this invention is to provide a means in an underwater spear gun whereby the spear velocity may be readily varied by a simple adjustment on the barrel of such gun. Other objects will be apparent from the following discussion.

These objects have been accomplished by providing a sub-aquatic gun in accordance with this invention. The novel gun is comprised of a perforated barrel, a throttling means tightly fitted to the bar-rel and adapted to slide over the surface of the barrel, a captive piston moving Within the barrel and designed to make contact with and eject the projectile, a blank cartridge to power the piston and firing means to detonate the blank cartridge.

The invention contemplates the use of dashpot action to brake a piston toward the end of its power stroke.

This principle is used along with a unique barrel feature to achieve velocity control over an underwater projectile which has been hitherto unattainable in a cartridge activated spear gun.

Reference is made to the following drawings in order to illustrate the concept of this invention, although it is to be understood that these drawings are merely exemplary and are not to be considered as limiting the scope of this invention. Similar numbers on different figures refer to identical parts.

FIGURE 1 is a top view of a sub-aquatic gun embracing one embodiment of the principles of this invention.

Referring now to the drawings, it is to be noted that the novel spear gun of this invention may be comprised of a conventional firearm such as a .22 caliber bolt action single shot rifle which has been modified by the addition of a new forward portion.

In FIGURE 1, the cocking handle 5 of the modified gun is pictured, while the receiver 6 and the bolt 7 are also illustrated in that figure. Possible alternative positions for the small ports 18 are shown in FIGURES 1 and 2 although if so desired, the ports may be located in both positions in the same firearm.

FIGURE 3 also illustrates the safety 8, the sear d, the firing pin 10, a blank cartridge ill and a vent hole 12. as they are positioned in the conventional part of the herein described spear gun.

Also illustrated in the drawings is the perforated barrel 13 with an accompanying closely fitted sleeve 14 which is so adapted that it can slide along the surface of the perforated barrel. The barrel perforations comprise a first series of lateral unobstructed ports 17 in the forward part of the barrel and a second series or" relatively smaller unobstructed ports 13 which are even closer to the forward part of the barrel. A captive piston is located inside the barrel and is comprised of, for example, a cup shaped member 15 having extending therefrom a piston tube 2%. The cylindrical guide members is; are integral parts of the captive piston. The large ports 317 are pictured as they are located in the wall of the barrel while the smaller ports 18 are located at an intermediate point between the large ports and the muzzle end of the barrel. The spear 19 is designed to fit inside the barrel, and if desired a cord or line may be attached in accordance with common practice to the spear at one end and to some point of the gun at the other end in order that the spear may be recovered.

The operation of the gun proceeds as follows. The blank cartridge is detonated by the firing pin it and the resulting expanding gases are exerted evenly against the head of the member 15. As the piston begins to move down the barrel, water between the piston wall and the barrel wall ahead of the guide surface to is forced out through the large and small ports. The piston velocity and the spear velocity are reduced as a result of this action since a great deal of energy is dissipated while forcing the fluid through these apertures.

However as the slidable piston proceeds in its path down the barrel, the guide member 15 eventually passes that point of the barrel wherein the large ports 17 are located. As the guide member passes these ports, there is no further opportunity for water to be forced out of these by-passed ports 17, and the only possible exit source for the compressed fluid is through the smaller ports near the muzzle end of the barrel. A greatly increased amount of energy is required to force the water through these small apertures, and consequently the piston velocity is lessened considerably, if not stopped altogether, as a result of this energy loss. The piston is thus braked in its movement down the barrel. In the event that the piston is only slowed in its movement, it will be eventually completely stopped by the movement of the piston guide surface 16 against the muzzle end of the barrel.

If it is desired to propel the spear with the highest possible velocity, the slidable sleeve on the barrel is adjusted so that all of the larger ports are open at the moment the cartridge is detonated. This allows the highest possible initial projectile velocity to be obtained since, as indicated above, only a minimum amount of energy is immediately dissipated when the fluid is forced through the larger ports. On the other hand, the lowest possible initial spear velocity can be obtained if the sleeve is positioned so that the larger ports are all blocked during the t =2 firing period. At this moment, the fluid displaced by the piston movement can only be discharged from the barrel through the small ports at the muzzle end of the barrel, and this reduces the piston velocity considerably since a great deal of energy is dissipated in forcing the fluid through these small apertures. By this unique innovation, a quick simple manipulation of the barrel sleeve by the operator preliminary to firing is sutficient to select the desired spear velocity and range even though blank cartridges of uniform power are always employed in the sub-aquatic gun.

Examples of instances wherein low velocity might be desired are where smaller fish are the targets for the projectiles or when it is desired to limit the range of these spears. Higher velocities might be advantageously employed when larger fish are being hunted or when for any other reason it is desirable to propel the spears to a greater distance.

As mentioned above, another advantage of this unique spear gun design is the ease with which it can be made ready for firing. Still another advantage is the reduced noise level achieved by this design as contrasted to the noise level usually associated with such underwater guns. This is a result of the fact that the expanding explosive gases are not able to escape readily from the unique design.

What is claimed is:

1. A sub-aquatic gun operative to propel a projectile comprising:

(a) a barrel member having a plurality of perforations disposed at one end thereof,

(b) a piston slidably disposed within and radially spaced from the interior of the barrel,

(c) a guide member mounted on said piston and in slidable contact with the barrel to define a cavity between said piston and said barrel,

(d) a projectile positioned to be engaged by the for ward end of said piston,

(c) said perforations communicating with said cavity and operative to permit introduction of fluid into the cavity,

(f) explosive means operative to drive the piston relative to the barrel effective to pump said fluid from said cavity through said perforations, and

(g) throttling means slidably mounted on said barrel movable to a position to limit the discharge of fluid from the cavity.

2. The device of claim 1 wherein said perforations comprise a first series of lateral unobstructed ports in the forward part of the barrel and a second series of relatively smaller unobstructed ports between the first series of ports and the muzzle end of the barrel.

3. The device of claim 2 wherein the throttling means comprises a sleeve movable to cover all of the first series of ports.

References Cited in the file of this patent UNITED STATES PATENTS 618,901 Peterson Feb. 7, 1899 1,338,676 Constantinesco et al May 4, 1920 1,351,017 Black-more Aug. 31, 1920 2,888,768 Taylor June 2, 1959 

1. A SUB-AQUATIC GUN OPERATIVE TO PROPEL A PROPEL A PROJECTILE COMPRISING: (A) A BARREL MEMBER HAVING A PLURALITY OF PERFORATIONS DISPOSED AT ONE END THEREOF, (B) A PISTON SLIDABLY DISPOSED WITHIN AND RADIALLY SPACED FROM THE INTERIOR OF THE BARREL, (C) A GUIDE MEMBER MOUNTED ON SAID PISTON AND IN SLIDABLE CONTACT WITH THE BARREL TO DEFINE A CAVITY BETWEEN SAID PISTON AND SAID BARREL, (D) A PROJECTILE POSITIONED TO BE ENGAGED BY THE FORWARD END OF SAID PISTON, (E) SAID PERFORATIONS COMMUNICATING WITH SAID CAVITY AND OPERATIVE TO PERMIT INTRODUCTION OF FLUID INTO THE CAVITY, (F) EXPLOSIVE MEANS OPERATIVE TO DRIVE THE PISTON RELATIVE TO THE BARREL EFFECTIVE TO PUMP SAID FLUID FROM SAID CAVITY THROUGH SAID PERFORATIONS, AND (G) THROTTLING MEANS SLIDABLY MOUNTED ON SAID BARREL MOVABLE TO A POSITION TO LIMIT THE DISCHARGE OF FLUID FROM THE CAVITY. 